U.S. patent application number 10/937211 was filed with the patent office on 2005-03-17 for earplug with bendable stiffener.
Invention is credited to Jenkins, John Allen JR., Tiemens, Jim.
Application Number | 20050056289 10/937211 |
Document ID | / |
Family ID | 34278878 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050056289 |
Kind Code |
A1 |
Jenkins, John Allen JR. ; et
al. |
March 17, 2005 |
Earplug with bendable stiffener
Abstract
Earplugs with soft foam bodies and with stiffeners in the
bodies, are molded by suspending the stiffener in the body mold
cavity using a pin (60) that extends into a passage (56) at the
rear of the body. Each stiffener is tapered in diameter, with a
rear end (34) of greatest diameter.
Inventors: |
Jenkins, John Allen JR.;
(San Diego, CA) ; Tiemens, Jim; (Laguna Niguel,
CA) |
Correspondence
Address: |
LEON D. ROSEN
FREILICH, HORNBAKER & ROSEN
Suite 1220
10960 Wilshire Boulevard
Los Angeles
CA
90024
US
|
Family ID: |
34278878 |
Appl. No.: |
10/937211 |
Filed: |
September 9, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60502789 |
Sep 12, 2003 |
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Current U.S.
Class: |
128/864 ;
128/846; 128/857 |
Current CPC
Class: |
A61F 11/12 20130101;
A61F 11/10 20130101 |
Class at
Publication: |
128/864 ;
128/857; 128/846 |
International
Class: |
A61F 005/37 |
Claims
What is claimed is:
1. An earplug comprising a soft body and a stiffener of resilient
material that is stiffer than material of said body and lying in
said body, said body having a front body portion for insertion into
a person's ear canal and said body having a body rear portion with
a body rear end that may remain out of the ear canal when said
front body portion lies in the ear canal, wherein: said body is a
molded part that lies around said stiffener; said stiffener rear
end has a stiffener pin-receiving hole whereby the stiffener has
been constructed to be held in a mold by a pin.
2. The earplug described in claim 1 wherein: said body is formed of
a foam material and said stiffener is formed of resilient
elastomeric material.
3. The earplug described in claim 1 wherein: said stiffener rear
end lies a distance of more than a millimeter forward of said body
rear end; said body rear portion has a hole that is of about the
same diameter as said stiffener hole and that is aligned with said
stiffener hole and that extends rearward to said body rear end.
4. The earplug described in claim 3 wherein: said earplug front
portion has a maximum diameter of about one-half inch to fit into a
human ear canal and seal it; said holes in said stiffener rear end
and in said body rear portion are each about 0.5 to four
millimeters in diameter.
5. The earplug described in claim 1 wherein: said stiffener has
front and rear ends, said rear end being at least 50% wider than
said front end.
6. The earplug described in claim 4 wherein: said stiffener rear
end is at least 200% of the width of said stiffener front end.
7. The earplug described in claim 1 wherein: said stiffener is in
the form of a tube with a tubular passage extending along most of
its length; and including a cord having a first end that projects
into said tubular passage and that is fixed therein, said cord
having an opposite end that is similarly fixed to another earplug
device.
8. The earplug described in claim 1 including: a band with opposite
ends and with a post at each end that projects into one of said
pin-receiving holes.
9. The earplug described in claim 1 wherein: said stiffener
includes a post that is elongated along an earplug axis, and said
stiffener has at least one flange that is surrounded by material of
said body and that extends at least partially radially by at least
half the distance between an outer surface of said post from which
said flange extends and an adjacent outside surface of said
body.
10. A method for forming an earplug with a stiffener for aiding the
insertion of a front portion of the earplug into the ear canal,
comprising: mounting the stiffener on a first mold part of a mold
that has a cavity, by inserting a pin that is fixed to said first
mold part, into a hole in a rear end of the stiffener; introducing
foamable material in the mold cavity, closing the mold cavity, and
allowing the foamable material to expand to fill the mold cavity
and lie around the stiffener; removing the earplug from the cavity,
including removing the pin from the stiffener.
11. The method described in claim 10 wherein: said stiffener is in
the form of a tube that has a passage forming said hole; including
inserting an end of a cord into said passage.
12. The method described in claim 10 wherein: said first mold part
has a first surface that forms a rear end of the cavity and a rear
end of the earplug; said step of mounting the stiffener includes
leaving a gap of at least one millimeter between said first surface
and an extreme rear end of said stiffener, whereby to conceal the
stiffener.
13. The method described in claim 12 wherein: said pin has a
diameter of about 0.5 to 4 millimeters.
14. An earplug comprising a soft and resilient body and a stiffener
of material that is more rigid than the material of said body, said
body having a front body portion with a front end, for insertion
into a person's ear canal, wherein: said stiffener has a front end
lying rearward of said body front end, said stiffener has a rear
end, and said stiffener is tapered in diameter with said stiffener
rear end being of larger diameter than said stiffener front
end.
15. The earplug described in claim 14, wherein: said body has a
rear surface, said stiffener rear end lies at least one millimeter
forward of said body rear surface, said stiffener has a rear
portion, and said stiffener rear portion has a hole in it, and said
body has a hole in it extending from said body rear surface to said
stiffener rear end and aligned with said hole in said stiffener
rear portion.
16. A method for forming an earplug with a stiffener, comprising:
mounting a stiffener that has an axis, that has a narrow front
portion, and that has a wider rear portion that has a plurality of
radially outer locations, in a mold by clamping said radially outer
locations between front and rear mold parts, and then molding
foamable material in the cavity.
17. The method described in claim 16 wherein: said stiffener rear
portion has a plurality of wings, with radially outer portions of
said wings forming said radially outer locations, and with said
wings forming spaces between said wings; said step of molding
includes flowing said foamable material between said wings and
rearward of said stiffener rear portion.
18. An earplug which includes a resilient and soft body and a
stiffener of material that is more rigid than the material of said
body and lying in said body, said earplug having an axis extending
in front and rear directions and having a front sealing portion
that seals the ear canal of a person who wears the earplug,
wherein: said stiffener has a plurality of stiffener portions lying
on a circle that is centered on said axis, as seen in a sectional
view taken normal to said axis, with a plurality of spaces lying on
said circle and separating said stiffener portions.
19. The earplug described in claim 18 wherein: said plurality of
stiffener portions are formed by a plurality of individual rods
spaced apart about said circle.
20. The earplug described in claim 18 wherein: said stiffener
includes an inner rod part that is elongated along said axis and
that lies within said circle, and a plurality of arms that project
at least partially radially from said rod part, to said stiffener
portions that lie on said circle.
21. The earplug described in claim 18 wherein: said stiffener
portions include at least two sections of a hollow cylinder that
lies on said circle.
22. An earplug that has an axis and that comprises a soft and
resilient body and a stiffener of foam material that is more rigid
than material of said body and lying in said body, with said foam
material of said body molded around much of said stiffener, said
body having a front body portion for insertion into a person's ear
canal and said body having a body rear portion with a body rear end
that may remain out of the ear canal when said front body portion
lies in the ear canal, wherein: said stiffener includes a post-like
portion and at least one flange projecting at least partially
radially, from said post-like portion and surrounded by said
foam.
23. The earplug described in claim 22 wherein: said at least one
flange extends at least 3 mm from said axis.
Description
CROSS-REFERENCE
[0001] Applicant claims priority from U.S. provisional patent
application Ser. No. 60/502,789 filed Sep. 12, 2003.
BACKGROUND OF THE INVENTION
[0002] Earplugs formed solely of soft resilient foam material are
difficult to insert into the ear canal. When the front end of the
earplug lies against the entrance to the ear canal and the rear end
of the earplug is pushed, the foam earplug collapses. During such
collapse, as shown at Z in FIG. 15, the front end of the earplug
enlarges in diameter and does not move into the ear canal. It has
been found that a core of stiffer material, as in the form of a
rod, can be placed in a soft resilient foam body to help insert the
foam body into the ear canal. U.S. Pat. No. 5,573,015 by Williams
shows a foam body molded around a stiffer core by extrusion.
[0003] Although an earplug with a stiffener that is exposed is
acceptable to many people, an earplug with stiffener that is almost
completely covered by the soft foam material of the body is often
more acceptable, at first. The largely concealed stiffener does not
remind a person that stiff material is to be inserted into his/her
ear canal and raise fears (unfounded) of discomfort by the presence
of stiff material. Thus, an earplug with a largely concealed
stiffener would be of value. A method for forming such earplug with
a largely concealed stiffener also would be of value.
[0004] Although a rod-shaped elastomeric stiffener helps in earplug
insertion, it makes the earplug stiffer against bending. Many
people have ear canals that are curved, so an earplug inserted into
one of the ears must bend to follow the curvature of the ear canal.
The stiffener resists bending, causing forces on the sides of the
person's ear canal and consequent possible discomfort to the
person. An earplug with a stiffener to help insertion, wherein the
stiffener was sufficiently stiff against column collapse but was
easily bent by the walls of the ear canal to avoid discomfort,
would be of value.
[0005] Methods for establishing a stiffer of any desired shape in a
mold cavity, at low cost, also is desirable.
SUMMARY OF THE INVENTION
[0006] In accordance with one embodiment of the invention,
applicant provides an earplug with a soft earplug body, a stiffener
extending within much of the length of the body, and an earplug
manufacturing method therefor, wherein the stiffener is axially
stiff but allows the body to easily bend. In one manufacturing
method for an earplug that is molded in a two piece mold, the
stiffener has a hole, or passage, in its rear end. A top part of
the mold has a pin that is inserted into the hole in a slight press
fit to hold the stiffener in the mold cavity. The stiffener may be
held with a space left between the rear of the earplug and the mold
top part, to conceal the stiffener in the final earplug. Foamable
material is placed in the mold cavity and the mold is closed, with
the stiffener held by the pin. When the foam material sets, the
earplug is removed, with foam lying all around the stiffener,
except for a hole at the rear of the earplug.
[0007] The pin on the upper mold part, that extends into a passage
in the stiffener, can extend into a passage that is meant to hold
an end of a cord of a type that holds two earplugs together. The
unfilled passage part left in the final earplug can more easily
receive a cord end.
[0008] A more bendable earplug is obtained by using a tapered
stiffener, with its rear end wide and its front end narrow. A
stiffener may include a plurality of stiffeners or stiffener
portions that lie on a circle (as seen in a sectional view of the
earplug) and with spaces between them.
[0009] An earplug body can be molded in a cavity, with a mandrel
extending along the axis to leave a stiffener inner cavity. When
the mandrel is removed, an elastomeric stiffener material is poured
into the inner cavity and allowed to solidify.
[0010] The novel features of the invention are set forth with
particularity in the appended claims. The invention will be best
understood from the following description when read in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a rear and side isometric view of an earplug of
one embodiment of the invention.
[0012] FIG. 2 is a partially sectional side view of the earplug of
FIG. 1.
[0013] FIG. 3 is a sectional view of the earplug of FIG. 2, but
with a modified stiffener.
[0014] FIG. 4 is a sectional view of a mold in which the earplug of
FIG. 3 is being molded.
[0015] FIG. 5 is a sectional view of another mold in which an
earplug of the type illustrated in FIG. 6 is being molded.
[0016] FIG. 6 is a partially sectional view of a pair of earplugs,
each of the type shown in FIG. 5, and with a cord with opposite
ends anchored in the earplugs.
[0017] FIG. 7 is an isometric view of an earplug with another form
of stiffener.
[0018] FIG. 8 is an isometric view of a stiffener of the earplug of
FIG. 7, which has a rear portion of enlarged width.
[0019] FIG. 9 is a sectional view of a mold, in which an earplug
with a stiffener of the type shown in FIG. 8 is being molded.
[0020] FIG. 10 is a sectional view of an earplug in a mold, with a
stiffener of another embodiment of the invention.
[0021] FIG. 11 is a side view of an earplug with a plurality of
stiffeners or stiffener portions spaced about a circle.
[0022] FIG. 12 is a sectional view taken on line 12-12 of FIG.
11.
[0023] FIG. 13 is a sectional view of an earplug similar to that of
FIG. 11, but with stiffeners or stiffener portions of a different
construction.
[0024] FIG. 14 is a sectional view of an earplug similar to that of
FIG. 11, but with stiffeners or stiffener portions of a different
construction.
[0025] FIG. 15 is a sectional view of an earplug fully inserted
into an ear canal that is curved, and also showing how a purely
foam earplug would collapse.
[0026] FIG. 16 is a sectional view of an earplug mounted at an end
of a head band.
[0027] FIG. 17 is a sectional view of an earplug with a stiffener
that has flanges.
[0028] FIG. 17A is an isometric view of just the stiffener of the
earplug of FIG. 17.
[0029] FIG. 18 is a sectional view of an earplug with a stiffener
that has parts of different stiffness.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] FIGS. 1 and 2 illustrate an earplug 10 which has a body 12
of soft resilient foam and a stiffener 14 that is of stiffer
material than that of the body and that extends part of the
distance along the earplug axis 16. The stiffener is constructed of
elastomeric material, which is resilient material having a Young's
modulus of elasticity of no more than 50,000 psi. It is possible to
construct the body of a slow recovery foam which is resilient but
with the recovery after deflection being delayed. The stiffener is
useful during earplug insertion into a person's ear canal, by the
person pushing against the rear end 20 of the earplug to force the
front end portion 22 of the earplug, which seals the ear canal, to
enter the ear canal. The earplug is elongated in front F and rear R
directions, also indicated by arrows L. The stiffener prevents the
body front end portion 22 from collapsing during insertion and
thereby increasing in diameter. The stiffener 14 shown in FIG. 2 is
in the form of a rod with an elongated narrow hole 24 in its rear
end. The body has a narrow hole 26 extending to the body rear end
20. Except for the narrow body hole 26, there is no indication that
there is a stiffener in the earplug. The hole 26 is long and narrow
enough, with a length in direction L more than the width in
directions W and more than the breadth in directions B (both
perpendicular to the length L) so the stiffener cannot be easily
seen.
[0031] FIG. 3 illustrates an earplug 30 with a stiffener 32 having
a wider rear end 34 than its front end 36 or middle 40. The wider
rear end assures that the stiffener will receive the forward
pushing force that a person applies to the rear end 42 of the body
44 during insertion into the ear canal, even if the person is
careless about applying the force along the middle of the earplug
rear end. The front end and middle are more likely to have to bend
to follow a curved ear canal and their smaller diameters facilitate
such bending. The wider, or larger diameter rear end should have a
diameter H that is at least 50% greater than the front end (at a
location before the curvature at the front end), with H actually
being more than twice G and preferably two to four times G. G is
taken rearward of a rounded end. When pushing the earplug rear end
during insertion, it is desirable to turn the earplug about a
quarter-turn to help insert the earplug. Such quarter turn is
achieved by turning the finger that is pressing on the earplug rear
end by a quarter turn. The larger diameter rear end of the
stiffener makes it easier to twist the earplug.
[0032] FIG. 4 shows a method by which the earplug of FIG. 3 is
formed. The body 44 of the earplug is molded in a mold cavity 50
formed between front or lower, and rear or upper mold parts 52, 54.
The stiffener 32 has been previously manufactured with a small
diameter (or small width if the hole is of noncircular
cross-section) hole 56 in its rear end. The top mold part has a
downwardly-projecting pin 60 that has a lower part 62 that lies in
the stiffener hole 56. The pin has an upper part 64 that extends
between the top of the stiffener and a bottom surface 66 of the
upper mold part that molds the rear end of the earplug body. The
stiffener is installed on the upper mold part as shown in FIG. 4,
prior to the body molding process. To mold the body around the
stiffener, foamable material is placed in the cavity 50 in the
lower mold part (or foamable material is injected into a closed
mold. Then the mold is closed, while the foamable material expands
and fills the mold. A vent (not shown) allows air to escape. After
the foam sets, the mold is opened and the pin 60 is pulled out of
the stiffener, leaving the narrow elongated hole in the earplug. It
is possible to fill the hole 26 (FIG. 3) with material, but
applicant prefers to not do that.
[0033] In one example, the earplug front portion has a diameter D
of 0.50 inch (12.5 mm), the pin 60 has a diameter of 0.5 mm to 4
mm, such as 1.5 mm, and the hole part 64 between the rear end of
the stiffener and the rear end of the body is longer than the pin
diameter, such as 6 mm long. The pin extends more than its diameter
into the stiffener hole 56 to closely control the orientation of
the stiffener in the mold. The pin front end that lies in the
stiffener during molding can have a few ribs to more easily provide
a press fit that prevents the stiffener from falling in the mold
cavity and that allows easy pin withdrawal. The soft elastic foam
body has a durometer of 1 to 10, shore A, while the stiffener is
preferably of the soft rubber type with a durometer of at least 30
shore A.
[0034] FIG. 5 illustrates an earplug 70 that is somewhat similar to
that of FIG. 4, except that the stiffener 72 is formed by a tube
(with or without a slot in one side) whose passage 74 extends most
or all of the way though the length of the stiffener. A pin 76 with
a front end 78 extends through a long length of the stiffener. The
earplug is formed in a mold 80 in a way similar to the earplug of
FIG. 4. However, the stiffener passage is long and the rear end 90
of the stiffener is flush with the rear end 92 of the body (or may
be recessed, or may even extend slightly rearward of the body).
FIG. 6 shows that the earplug is intended to receive an end 94 of a
cord 96. The cord extends between two earplugs 100, 102, with the
ends 94 of the cord inserted into the tubular stiffeners in the
earplugs and held therein as with adhesive, or with barbs on a
stiffened cord end, or other cord attachment means such as
ultrasonic welding, heat staking, etc. Such corded earplugs are
used to minimize the possibility that a single earplug will fall
into a vat of material being processed.
[0035] FIGS. 8 and 9 illustrate a stiffener 110 with a tapered post
part 111 and with a radial (with respect to the earplug axis 112)
projection 114 at its rear end. The projection 114 has recesses
that form wings 115. The wings forms radially outermost locations
121-124 and gussets 126. The locations 121-124 are clamped between
upper and lower parts 130,132 of the mold 134. When foamable
material is placed in the mold cavity 140, the foam material which
will form the earplug body, surrounds the stiffener, except at the
four location 121-124. FIG. 7 shows the final earplug, which has
four small stiffener locations such as 122, 123 that can be
seen.
[0036] FIG. 10 illustrates an earplug 142 similar to that of FIG. 4
but with a stiffener 143 having a wider rear end. The amount of
stiffener material is minimized by forming the stiffer rear end
with gussets 145 that support a wide circular rear end 146 on a
post-like part 147.
[0037] FIGS. 11 and 12 illustrate an earplug 150 with a stiffener
152 formed by a plurality of rods 161-164 of material that is
stiffer than the material of the soft foam body 170. Each of the
rods is thin and therefore easily bent to avoid discomfort when the
earplug is inserted into a curved ear canal, such as shown at 172
in FIG. 15. The four rods of FIG. 12 lie on a circle 174 centered
on the earplug axis 176 and there are spaces 178 between them. The
rods are each partially supported by the foam body, to resist body
collapse during insertion into the ear canal. FIG. 13 shows a
variation, wherein the stiffener includes two tube halves 180,182
of a tube centered on the earplug axis 184. In both FIGS. 12 and 13
the stiffeners each include a plurality of stiffeners, or stiffener
portions, spaced apart along a circle that is centered on the
earplug axis, with a plurality of spaces 178 or 190 between
them.
[0038] FIG. 14 illustrates an earplug 200 with a stiffener 202
having a plurality of stiffener portions 211-214 that are spaced
apart along a circle 216 that is centered on the earplug axis 220.
The particular stiffener 202 has a center portion 222 lying at the
axis and four arms 224 that connect the center portion to the
stiffener portions 211-214 that lie on the circle 216. An advantage
of the stiffener 202 is that the stiffener portions 211-214 and
thin center portion 222 are easily bent when inserted into a curved
ear canal. However, the stiffener portions 211-214 resist column
collapse of the earplug body 224. The stiffeners of FIGS. 12-14 may
be of constant cross-section along their entire lengths.
[0039] FIG. 16 illustrates an earplug 230 which is attached to an
end of a head band 231, such as the type shown in U.S. Pat. No.
6,138,790. The earplug has a body 232, and has a stiffener 234 with
a hole or passage 236. A barbed post 240 has been forced into the
stiffener passage. A rear end 242 of the post is anchored in the
head band. An identical earplug and post lie at the opposite end of
the band.
[0040] FIG. 17 shows an earplug 250 with stiffener 251 having a
post 257 that is tapered, and with flanges 252, 254, 256 projecting
radially outwardly (with respect to axis 260) and rearward R from
the post. The stiffener is encased in a soft resilient foam body
262 by being molded in the body. The flanges, which are in the
shape of truncated cones that extend 360.degree. about the axis
260, increase the blockage of noise. The stiffener is of material
that is stiffer and more dense than the material of the body, and
is preferably at least twice as dense. When noise encounters an
interface between materials of different densities, more of the
noise is blocked. The fact that the flanges extend at a radially
outward-rearward incline helps in deflecting the flanges inwardly
toward the axis as the earplug is installed in the ear canal. The
flanges make the earplug overall more effective in blocking a range
of sound frequencies. The flanges near the front end are of smaller
diameters to minimize resistance to earplug compression during
initial earplug insertion. The flanges add almost no resistance to
bending of the earplug. In an earplug of 12.5 millimeter diameter,
and therefore 6.25 mm radius (from axis 260), the flanges have a
thickness of about 0.6 mm. At least one flange projects to a
distance of at least 3 mm from the axis, and at least 2 mm beyond
the stiffener portion that it projects from. The flanges preferably
extend radially at least about half the radial distance between the
outsides of the post and the outside of the body.
[0041] FIG. 18 shows an earplug 270 with a soft foam body 272 and
with a stiffener 274. The stiffener has two portions 280-282 of
materials of different stiffness but with the materials of both
portions being stiffer than the material of the body 272. In one
example the body is of foam having a stiffness of 2 shore A, the
stiffener portion 280 has a stiffness of 10 shore A, and the
stiffener portion 282 has a stiffness of 40 shore A. The stiffener
is tapered in diameter, being widest at its rear end. The stiffest
material such as material of stiffener portion 282 is tapered in
thickness, being thickest at the rear end.
[0042] Thus the invention provides earplugs with soft resilient
foam bodies (including slow recovery foam) and with elastomeric
stiffeners bonded to the bodies by being molded one to the other.
All of the illustrated earplugs are symmetric about their axis. An
earplug with an axially aligned stiffener, is molded in a mold
cavity, with the stiffener held by at least one pin that is
preferably a centering pin, that extends into a hole at the rear
end of the stiffener. The stiffener may or may not be concealed,
especially where the stiffener is a tube that will receive an end
of a cord that holds a pair of earplugs together. The stiffener may
have a wide rear end, and narrow front end. A wide rear end may
have locations that are clamped by parts of a mold to hold the
stiffener in place. The stiffener may have a plurality of stiffener
portions spaced along a circle that is concentric with the earplug
axis. The stiffener may have flanges that help block noise. The
stiffener may have radially inner and outer parts of different
stiffness.
[0043] Although particular embodiments of the invention have been
described and illustrated herein, it is recognized that
modifications and variations may readily occur to those skilled in
the art, and consequently, it is intended that the claims be
interpreted to cover such modifications and equivalents.
* * * * *